Control of lung function Flashcards
Where are the 4 main respiratory nuclei and what are they?
Medulla Oblongata
Dorsal Respiratory group
Ventral respiratory group
Apneustic centre
Pneumotaxic centre
What is the dorsal respiratory group responsible for?
Inspiratory centre
Main ‘controller’ of inspiration
Set the ‘rate’
What is the ventral respiratory group responsible for?
Expiratory centre
Inactive during quiet breathing
Inhibit apneustic centre
What is the apneustic centre responsible for?
Stimulates activity in DRG
Inhibited by pulmonary afferents
What is the pneumotaxic centre responsible for?
The ‘inspiratory off switch’
Regulates depth & frequency
What groups are responsible for inspiration and expiration?
Inspiration: DRG, Apneustic centre
Expiration: VRG, Pneumotaxic centre
How do the different respiratory nuclei control eachother?
What centres are active at the start and end of inspiration?
Start: Apneustic centre
End: Pneumotaxic centre
What kind of pattern is shown in the respiratory pacemaker?
A ‘ramp potential’ pattern
How is the diaphragm innervated?
Phrenic nerve
How are the intercostal muscles innervated?
Intercostal nerves from T1-T11
How are the lungs themselves sympathetically/parasympathetically innervated?
Symp: From sympathetic trunk ganglia
Parasymp: Jugular ganglion in pons
-Both fuse at pulmonary plexuses
What kind of vessel walls do you have in normal circulation?
What kind of vessel walls do you have along the blood brain barrier?
Describe the transfer of molecules through the blood brain barrier
CO2(due to high lipid solubility) passes from capillary to CSF
CO2 in CSF turns in carbonic acid, which dissociates
H+ from acid passes into the medulla into projections from the DRG
Where are irritant receptors found and what is their function?
Trachea
Afferent receptors embedded within and beneath airway epithelium
Leads to cough: which involves forceful expiration against a closed glottis with sudden glottal opening & high velocity expulsion of air
Where are stretch receptors found in the CP circuit and what is their function?
Lobar bronchi
Excessive inflation of lungs activates pulmonary stretch receptors
Afferent signals to respiratory centres inhibit DRG and apneustic centre and stimulate pneumotaxic VRG
Inspiration inhibited & expiration stimulated
Where are J-receptors found and what is their function?
Alveolar sacs
Sensitive to oedema and pulmonary capillary engorgement
Increases breathing frequency
How does pH affect proteins?
By altering their 3D stucture
What occurs to chloride ions as carbonic acid dissociates in blood cells?
Cl- enters the cell to balance the charge equilibrium
pH equation
pH = -log(10)[H+}
def Alkalaemia
Higher than normal blood pH
def Acidaemia
Lower than normal blood pH
def Alkalosis
Conditions generating a high pH
def Acidosis
Conditions generating a low pH
How does the speed of pH buffering differ in the kidneys/lungs?
Changes in ventilation issue a rapid response
Changes in renal secretions issue a slow response
Where are the peripheral chemoreceptors and what what nerves are they innervated by?
Aortic: X
Carotic: IX
What 2 factors elicit an emotional response which affects the respiratory control center?
Higher brain centres
Special senses
How are the ventilation groups in medulla innervated by exercise?
Efferents from primary motor cortex to gross skeletal musculature partly innervate medulla
Proprioceptive afferents from muscle spindles & golgi tendon organs innervate medulla on way to brain
